1. Field of the Invention
The present invention relates to a method for implementing vascular anastomosis in the attachment of a graft vessel to a target vessel such as a coronary artery, and subsequently creating a passageway between the vessels in order to establish fluid flow communication therebetween. The invention is further directed to the provision of novel devices which are utilized in implementing the steps of attaching a graft vessel to a target vessel such as a coronary artery through vascular anastomosis, and thereafter creating a fluid flow passageway therebetween.
The concept of anastomosis in implementing the attachment of target vessels, for instance, such as coronary arteries and other body vessels which are subjected to a fluid flow, such as blood to a graft vessel which is intended to be placed in fluid flow communication with the target vessel is well known in the medical technology.
Quite frequently, the attachment or anastomosis of the vessels is implemented through the intermediary of hand suturing of the graft vessel to the target vessel, in effect the coronary artery, necessitating the carrying out of extremely difficult and highly dangerous surgical procedures.
Generally a surgeon will perform an arteriotomy on the coronary artery at a location which is downstream from a blockage; however some flow of blood may still be present in the diseased artery. Occasionally the blood flow through the artery is temporarily occluded by means of a clamp in order to be able to incise the coronary and then perform the anastomosis with a minimal blood leakage. Nevertheless, the occluding of the artery occasionally dislocates plaque which lines the intima of the diseased coronary artery, enabling the plaque particles to migrate downstream, and thereby creating a scenario for the propagation of subsequent complications over time which may be readily life threatening to a patient. Even in the event that the coronary artery is occluded prior to the arteriotomy, it is usually necessary to manage any blood leakage which may be encountered by means of a CO2 blower. Thus, it may be advantageous to be able to perform the anastomosis of the graft vessel to the coronary artery or any target vessel without first having to implement an arteriotomy on the target vessel or coronary artery.
Moreover, the cardiac surgeon must exercise considerable care in order to stitch the intima of the graft vessel to the intima of the coronary artery in order to promote healing at the location of the passage way which has been created between the newly joined graft vessel and the coronary artery. In an ideal situation, the cardiac surgeon intends that the edges of the incision of one vessel are to be perfectly aligned with the mating or opposite edges of the incision of the other vessel, enabling endothelial tissue to quickly form a smooth seam joining the vessels with a minimum build-up of intraluminal tissue mass which may conceivably restrict blood flow subsequent to the joining of the vessels. A conventional stitching method using a running suture also may result in so-called purse stringing or bunching of tissue at various locations along the perimeter of the anastomosis, with the resulting potential of creating subsequent occlusions at those locations. In addition to the foregoing, cardiac surgeons presently slice the coronary artery with a small scalpel, at times utilizing a large number of strokes in order to cut through layers of the interior walls of the artery, and by approximating the length of the incision required based on the size of the graft vessel. This necessitates extreme care to be exercised in order to avoid cutting the posterior wall of the artery.
Consequently, it is imperative that methods and apparatus be developed for forming an anastomosis of a graft vessel to a coronary artery or similar target vessel without first having to create an arteriotomy on the target vessel or artery. Moreover, also desirable is to be able to join the vessels in an anastomosis prior to creating a passageway facilitating fluid flow therebetween in order to ensure that the opposing edges of the incisions in the graft and target vessels are perfectly aligned and stabilized, and with the avoidance of any purse stringing or bunching of the tissues along the anastomosis perimeter. It is also necessary that a method be developed for incising the artery without the possibility of such posterior wall cuts having to be implemented, and with only a minimal chance of rendering the incisions to be either too lengthy or too short at the location of the anastomosis.
It has also been ascertained that bio-adhesives may be utilized in the joining together or anastomosis of blood vessels; however, in the event that an arteriotomy is implemented prior to adherence between the vessels, it is a possibility that the surgeon may inadvertently apply adhesive material onto the intima of the vessels which are to be joined, thereby impeding the appropriate healing of the joined vessels. Thus, there is a need for a method which will alleviate this potential danger to the patient in being able to join the vessels without exposing the intima of either vessel to the bio-adhesive.
2. Discussion of the Prior Art
Although numerous publications are currently available which to varying degrees concern themselves with this particular technology, none of them clearly or satisfactorily provide teachings regarding vascular anastomosis methods or devices which will provide for the joining of a target vessel, such as a coronary artery, to a graft vessel prior to the cutting of a fluid flow passageway between the graft vessel and the target vessel so as to generally, to a considerable degree, alleviate the difficulties and shortcomings encountered in the medical technology.
Nobles et al. U.S. Pat. No. 5,944,730 discloses a device and method for assisting in end-to-side anastomosis wherein a sealing device pierces the one vessel and then forms a inner seal around an inner wall of an incision in an arterial blood flow or target vessel. Thereafter, a graft vessel is attached to the target vessel or artery, and appropriate suturing implemented, whereupon the seal is then withdrawn through the graft vessel providing for fluid or blood flow communication between the coronary artery and the graft vessel.
Stefanchik et al. U.S. Pat. No. 6,015,416 discloses an end-to-side anastomosis between two vessels, wherein a passageway is initially created between the vessels and thereafter a plow structure of a surgical anastomosis instrument is withdrawn subsequent to effectuating anastomosis therebetween.
Troutman U.S. Pat. No. 5,041,127 discloses an offset point surgical needle adapted to pierce through the walls of a vessel which is to be subjected to anastomosis with another vessel.
Whitehall et al. U.S. Pat. No. 3,019,789 discloses an anastomosis clamp for the intimal-to-intimal anastomosis of two vessels, and wherein sutures are to be applied to the location of the anastomosis subsequent to the formation of a flow passageway between the vessels.
The foregoing publications all entail the forming of passageways which permit blood flow between a coronary artery or target vessel and a graft vessel prior to anastomosis, and which are subject to the drawbacks and disadvantages described hereinabove.
Other publications also concern themselves with different types of devices and methods for performing anastomosis between blood vessels or graft vessels.
Bolduc et al. U.S. Pat. No. 5,976,159 discloses a surgical clip and method for tissue approximation, which enable the end-to-end anastomosis and method for tissue approximation, and which also enable the end to the side anastomosis between a coronary artery and a graft vessel subsequent to the forming of a flow passageway therebetween.
LeMole U.S. Pat. No. 5,893,369 describes a procedure for bypassing an occlusion in a blood vessel wherein an end-to-side anastomosis is performed between two vessels and wherein a graft vessel initially has a seal element punch a passageway through the target vessel or artery. Thereafter the graft vessel is attached thereto by means of suitable clamps, whereupon subsequent to suturing the seal element is withdrawn through the graft vessel.
Walsh et al. U.S. Pat. No. 4,657,019 describes an anastomosis device wherein forceps are adapted to engage ring shaped anastomosis elements in order to perform end-to-end anastomosis between a, artery or target vessel and a graft vessel. This also entails the formation of a flow passageway prior to carry out the anastomosis.
Gifford, III et al. U.S. Pat. No. 5,695,504 describes various methods and apparatus for performing anastomosis in an end-to-end and side vascular surgery, particularly coronary artery bypass surgery. In this instance, a passageway is formed in a target vessel or coronary artery wherein ring shaped anastomotic couplers are introduced through an incision formed therein and then connected to a graft vessel. This also entails forming a blood flow passageway between the vessels prior to the anastomosis thereof.
Similarly, Gifford, III et al. U.S. Pat. No. 5,817,113 discloses the formation of a flow communication in a target vessel, such as coronary artery, prior to anastomosis with a graft vessel.
Kaster U.S. Pat. No. 4,368,736 describes an anastomotic fitting for performing an end-to-side anastomosis between a target vessel, such as an aorta or coronary vessel, and a graft vessel. In that instance a passageway facilitating blood flow between the vessels is formed prior to the anastomosis which is implemented by way of surgical clips engaging the tissue of the target vessel.
Spence et al. U.S. Pat. No. 5,868,763 discloses an apparatus and method adapted to perform anastomosis, wherein side-to-side anastomosis between two vessels is implemented subsequent to the forming of a passageway between the vessels, which enables blood flow through the vessels prior to completing the anastomosis.
Finally, International Publication WO 99/37218 (PCT/US99/01182) provides a system for performing vascular anastomosis in which an opening is formed in a target vessel, such as a coronary artery, and subsequently an anastomosis is performed in the attachment of a graft vessel thereto.
All of the foregoing publications require the termination of blood flow through the target vessel during implementing of the foregoing procedures, or necessitate lengthy surgical procedures which includes considerable risk to patients and which are subject to high degrees of morbidity and potential mortality while necessitating lengthy hospital stays for the patient.